1. Field of the Invention
The present invention relates to a water-cooled engine, and more particularly, to a piping structure between a water pump and a thermostat valve.
2. Description of the Background Art
A water-cooled engine has a cooling system including a water jacket, a thermostat valve, a radiator, and a water pump, with water hoses extending therebetween. Moreover, such a structure is known where a bottom bypass type thermostat valve is utilized such that the thermostat valve and the water pump are connected with a bypass hose, and cooling water is returned from the thermostat valve to the water pump when the temperature of the water is low. One example is shown in Japanese Utility Model Publication No. 8-5326.
Generally, in a single cylinder engine or parallel multi-cylinder engine, a thermostat and a carburetor are disposed within a space above a crankcase, which is provided close to a cylinder. Moreover, a starter motor is provided above the crankcase. Further, a water pump is provided under the crankcase.
Therefore, a space for adjusting the carburetor tends to be reduced because of water hoses that interconnect the thermostat valve, water pump, water jacket, and radiator. Further, the number of hoses increases when a bottom-bypass-type thermostat valve is used. Thus, it is difficult to create a space for such hoses without affecting the layout of other parts which are provided nearby.